1. Field of the Invention
The present invention relates to an electromagnetic switching device comprising a movable contact-holder fitted with a set of contact bridges that operate in conjunction with fixed contacts, also comprising an electromagnet composed of a coil, a fixed framework and movable framework, the movable framework of the electromagnet being associated with the contact-holder and causing the contact-holder to move in translation in order to open or close the contacts.
2. Discussion of the Background
French patent FR 2518308 discloses a contactor-type electromagnetic switching device comprising an electromagnet powered by an alternating current. The contact-holder of the contactor has a lower cavity containing the movable framework of the electromagnet, the movable framework being fastened by means of a pin passing through the framework and introduced into the body of the contact-holder on each side of the cavity. The movable framework of the electromagnet is the type of E-shaped magnetic circuit commonly used for electromagnets powered by alternating currents and the way the contact-holders are assembled is consequently appropriate to the invention. However, this mode is difficult to implement for the blade-type movable framework used in electromagnets powered by direct currents, the blade being too thin to allow a fastening pin to pass through it.
U.S. Pat. No. 5,281,937 discloses a contactor-type electromagnetic switching device comprising a movable framework of an electromagnet consisting of a plane blade whose shape is suitable for it to be fastened to the mobile contact-holder of the contactor by means of elastic clipping feet provided on the contact-holder. However, this fastening method cannot be adapted directly to a movable framework consisting of an E-shaped magnetic circuit.